Recurrent mitral regurgitation with haemolytic anaemia after MitraClip procedure: an autopsy case report.

Background: Transcatheter edge-to-edge mitral valve repair (TMVr) has been developed as an alternative therapeutic approach to patients with severe mitral regurgitation (MR) at high-surgical risks. Single leaflet device attachment (SLDA) is a well-known complication after the TMVr procedure, while an autopsy case experiencing haemolytic anaemia has been scarcely reported. Case summary: A 79-year-old woman presented with New York Heart Association Class 3 congestive heart failure due to severe MR. The Heart Team planned TMVr using the MitraClip considering a high-surgical risk due to the history of open-chest surgery. The procedure was successful with two clips and a significant reduction of MR was confirmed. On the 12th day after the procedure, congestive heart failure was worsened and a transthoracic echocardiogram revealed severe MR suggestive of SLDA. Blood test showed normocytic anaemia with serum lactate dehydrogenase level elevation and renal function deterioration. We diagnosed as mechanical haemolysis induced by recurrent MR because of a decrease in serum haptoglobin level and the presence of schizocyte in the blood smear. Despite our intensive medical treatment, she died on the 119th day after the procedure. The pathological autopsy demonstrated that the ruptured leaflet was thickened with layered structure and severe fibrosis, while there were no findings of calcification, vegetations, or abscesses. Discussion: Single leaflet device attachment and subsequent mechanical haemolysis are rare but fatal complications after TMVr with the MitraClip. Not only degenerative MR but also functional MR may be associated with valve leaflet degeneration. A possibility of mechanical haemolysis should be considered when recurrent MR is observed after TMVr.